I. Field of the Invention
The present invention relates to the field of wireless communications. More particularly, the present invention relates to a novel and improved system that encrypts the information used to authenticate a wireless communications device.
II. Description of the Related Art
The security of a wireless communications system is an important factor in determining the quality of the system. A major security threat to wireless communications systems is the cloning of wireless communications devices. Each wireless communications device has an authentication key (A-Key). The wireless communications system uses the A-key along with other information to authenticate the wireless communications device, and the wireless communications device may be denied service without proper authentication.
This other information used with the A-key to authenticate the wireless communications device is typically broadcast over the air and is relatively easy to obtain. The A-key is the one piece of information that should remain absolutely secret within the wireless communications device and the wireless communications system. If the A-Key is obtained, then the legitimate wireless communications device can be readily cloned given the available access to the other information. The wireless communications system is unable to differentiate between the legitimate wireless communications device and the clone.
Unfortunately, the user of the legitimate wireless communications device is improperly billed for calls made with the clone. The wireless communications system typically forgives the fraudulent bills, but the reputation of the wireless communications system is damaged. The wireless communications system must also increase capacity to handle fraudulent calls without obtaining any associated revenue. The cost of the increased capacity is typically passed on to legitimate wireless communications device users.
The wireless communications system has an authentication system to authenticate wireless communications devices. The authentication system and the wireless communications device each use the A-key and a shared random number to generate identical Shared Secret Data (SSD). The authentication system and the wireless communications device periodically update the SSD. To authenticate a wireless communications device, the authentication system and the wireless communications device share another random number. The authentication system and the wireless communications device each use the SSD and this other random number to generate an authentication result. The wireless communications device is authenticated if it transfers a matching authentication result to the authentication system. Although technically possible, it is not computationally feasible to derive the A-Key from the authentication result considering the vast amount of computing power and time required.
The authentication system maintains large databases of A-Keys for millions of wireless communications devices. The mass storage of A-Keys poses a great risk. If a person obtains access to the authentication system, then that person can potentially clone large numbers of wireless communications devices and seriously undermine the security and integrity of the wireless communications system. The wireless communications system would be greatly improved by a technology that improves the security of A-Keys in a wireless communications system.